Friday, 15 June 2018

FRI 15 JUN 2018

Today marks the end of the chasecation for another year, it's been great fun with some fantastic storms at times and I can't wait to be back in the Plains sometime in May/June 2019. While I wait for the flight home, I leave with some statistics from this year's chase:

Thursday, 14 June 2018

THU 14 JUN 2018

SPC Forecast

SPC Tornado Probability Forecast

Today is our last full day in the U.S.A. before we fly back to the U.K. tomorrow - so sadly we can't chase the supercells in North Dakota / Canada, and had just a short amble from Goodland (KS) to our hotel for the night in the Denver metroplex (CO), including a trip to Applebee's in the evening. En-route to Denver we had a short diversion to chase a weak high-based (13,000ft!) thunderstorm north of Flagler (CO) - but sadly didn't witness any lightning. We hit 102F on the car thermometer today, our hottest day so far this trip.
The sad feeling that the chasecation is coming to an end is beginning to sink in...

Wednesday, 13 June 2018

WED 13 JUN 2018

With the chase soon coming to a close, we need to be in the Denver area by the end of the week for our flight back to the U.K. Weather looks quieter for the next few days, as the focus shifts from the northeastern states today to the Dakotas/Canada for tomorrow - too far north for us to venture.

SPC Forecast

SPC Tornado Probability Forecast

We left Woodward (OK) late morning and headed north for many hours, via WaKeeney (KS) for a bite to eat, before ambling up into NE Colorado to see if we could catch a thunderstorm developing on the retreating dryline / trough intersection. A couple of storms went up, but they struggled to become organised. We parked outside of Wray (CO) for a bit to see if we could get any lightning shots, but sadly not enough cloud-to-ground strikes to make it worthwhile.

Radar with our GPS location (blue circle)

As we drove back through Wray, the tornado sirens started followed soon after by multiple emergency vehicles driving about the town with their sirens and lights on too - I have no idea why! The storm was barely severe, let alone tornadic, and was pretty much on it's last legs.

We left the storm at Haigler (NE) and headed to Goodland (KS) for the night.

Tuesday, 12 June 2018

TUE 12 JUN 2018

We left Salina (KS) at midday and travelled a couple of hours southwestwards to Medicine Lodge (KS). A near-stationary cold front was located nearby, and would hopefully be intersected by an old outflow boundary somewhere in south central Kansas.

After a relaxed mid-afternoon lunch (as no storms had developed yet), we trundled west to Coldwater (KS) - and en-route observed a developing thunderstorm to our southwest.
We essentially followed this thunderstorm for the rest of the day - it split twice, with the right-mover becoming the dominant cell in both cases, and forcing us to nudge a little south towards Buffalo (OK). The supercell then really started to wrap up, with some amazing structure at times and multiple attempts at developing a wall cloud.

Pete capturing the storm while trying to dodge lightning

The storm was only moving at 5mph to the south, since it was anchored to a boundary, giving us plenty of time to park up and observe the storm. The slow motion of the storm, and the vast array of gridded dirt roads in this part of Oklahoma, meant for an enjoyable chase.

A new meso developed on the western flank of the original storm, and so begun multiple occasions of back building where the new cell to the west became the new dominant cell, and we continued to nudge west past Laverne (OK) towards Beaver (OK).

From an initially lone supercell...

... to a constantly backbuilding line of thunderstorms

Sadly, despite many attempts, not a single tornado was produced, and once the thunderstorms became outflow-dominant we ended the chase and headed to our hotel in Woodward (OK).

The supercells tried many times to develop wall clouds, but sadly no tornadoes...

Monday, 11 June 2018

MON 11 JUN 2018

Position day today, ready for Tuesday’s activity in SW Kansas - or so we thought, until I woke up this morning and realised the cold front was a little slower moving than forecast the previous day, and it might be doable to intercept a couple of thunderstorms on the tail end towards evening as part of our journey south.

So we left Fort Pierre (SD) fairly early and started our long journey south to SE Nebraska. Grabbed some lunch mid-afternoon in Grand Island (NE), and then headed east towards Lincoln (NE) to intercept thunderstorms developing along the cold front.
This proved rather tricky - we needed to get east of the line to be able to look back into the storms for any tornado potential - but each time we made an attempt to get through the line of storms, they kept back-building.

Looking at the rear side of the line of severe thunderstorms

Radar showing our GPS location (blue circle) as we tried multiple times to get to the other side of the line of thunderstorms. Plenty of tornado warnings (red polygons)

We had multiple attempts to break through, but in the end gave up and ended the day in Salina (KS) - hopefully a little closer to our target for tomorrow.

After a bite to eat in Spearfish (SD), we nudged a little ways north to Bell Fourche Reservoir, where we sat next to the water watching cumulus attempting to build along the cold front and dryline. Eventually the convection became more robust and off we went after a impressive looking thunderstorm south of Buffalo (SD). As we approached, the storm became tornado-warned - road options were less than ideal, and trying to keep up with the storm, given the lack of roads, was proving tricky.

Looking north from Belle Fourche (SD) at the developing thunderstorms

Radar and our GPS location (blue circle). Red polygon tornado warning

We saw a thin rope funnel extend two thirds of the way to the ground - but to my knowledge no full tornado was ever reported with this storm. We then got cut off by a new thunderstorm developing overhead, and were then stuck in heavy rain and hail for quite some time as we tried to get out of the storm and get round its southern flank (and ultimately ahead of it). Eventually we did, and headed east to Faith (SD) to watch the line of thunderstorms approaching, with a spectacular gust front - one of the best I’ve ever seen, especially given the stark contrast of colour between electric blue in the ‘whales mouth’, which was flashing constantly with lightning, and the orange of the setting sun behind. Part of this line of thunderstorms became briefly tornado-warned once again, but alas looked visually unlikely to produce anything (and it didn’t).

Shelf approaching Faith (SD), looking west

Gust front approaching from the west

Behind the gust front - often referred to as the 'whales mouth'

Radar and our GPS location (blue circle). Red polygon tornado warning

We eventually left the storms and headed to a hotel in Fort Pierre (SD) for the night - an interesting city in the sense that Fort Pierre is located on the western banks of the Missouri river and is therefore in the Mountain Time Zone (MDT), while the city of Pierre on the other side of the river is located in Central Time Zone. However, everyone in Fort Pierre apparently goes by Central Time (which is 1 hour ahead) except the bars - because it means they can stay open an hour longer relative to the ‘working day’!

Saturday, 9 June 2018

SAT 09 JUN 2018

The risk of severe thunderstorms today was primarily reserved for eastern Iowa - some 6+ hours travel time to get into position, with chasing then on top. This would also then put us out of position for any potential thunderstorms on Sunday - so we chose today to be a travel day to get closer to where we need to be on Sunday.

We left Valentine (NE) around lunchtime and drove to Sturgis (SD). A few marginally-severe thunderstorms had developed over NE Wyoming, which then drifted into western South Dakota by evening. The nearest storm was about 35 miles from our location - we contemplated chasing it, but it weakened quite rapidly, so in the end decided not to. Hopefully we're in a good position for storms tomorrow, though with a strong cap it's likely they may not fire until quite late in the day.

Friday, 8 June 2018

FRI 08 JUN 2018

We headed north after lunch in Chadron (NE) across the border towards Buffalo Gap (SD) towards a supercell that had developed over the Black Hills northwest of Rapid City (SD). Some of the CAMs (convection allowing models) were suggesting that this storm would weaken as it drifted away from the mountains, while new storms were expected to fire up well to the east.

Right on cue, towering cumulus were visible to our east, and so we headed towards Interior (SD) where an updraft developing overhead produced some marble sized hail and a lot of rain / lightning. This cluster of thunderstorms was fast growing in size, and we had some work to do to get around to the south side - due to limited road options we had to drive round the northern then eastern flank of this developing MCS (mesoscale convective system) in order to get ahead of it, as it began to move to the SE.

On the SE side of the storm complex, a nice gust front was visible as this portion of the storm bowed out. We ambled southwards back over the border towards Valentine (NE), with the storm, now forming a squall line, very slowly drifting southeastwards towards us. The storms were very active with lightning, but most was inter-cloud or hidden in the wall of rain - with, by this stage, very little cloud-to-ground lightning, and hence not much worth taking a photo of.

Gust front to the west of Mission (SD)

Mammatus to the south of Valentine (NE)

Eventually we gave up as darkness fell and found a hotel in Valentine (NE) where we sat and let the storms pass over us - some of the cloud-to-ground lightning was very close with near-instant thunder.

Thursday, 7 June 2018

THU 07 JUN 2018

Two main targets at play today - southeast Wyoming close to the warm front / dry line intersection, or northeast Wyoming into southeast Montana where the warm front was likely to interact with a couple of outflow boundaries. Either way, shear was a little marginal for organised storms / supercells, perhaps slightly better in northeast Wyoming / southeast Montana.

We opted for the southeast Wyoming target, and left our hotel in Casper (WY) to travel to Wheatland (WY) for lunch. Just after we'd finished eating lunch, I spotted quite a decent a mid-level funnel hanging underneath a very skinny updraft to our north...

We nudged east and parked up at Torrington (WY) for quite some time, watching several thunderstorms pulse and look good initially, but only to then weaken. Another brief funnel was spotted above our chase vehicle just east of town. Dave Ewoldt joined us once again, as we tried multiple times to relocate to capture some lightning, but each attempt was met with the thunderstorm weakening and constantly moving away to the east.

Mammatus display just east of Torrington (WY)

Mammatus display to end the day, east of Lusk (WY)

Eventually we gave up and headed to Chadron (NE) for the night. I don't think there were any tornadoes anywhere in the U.S. today - most of our storms seemed to struggle for organisation and seemed very 'pulse type'.